There are known sacks made of plastic or natural material (paper or vegetable matter) forming a reticular tissue, which usually has a rectangular mesh, the mouth of the sacks being provided with linear flexible closing and holding means such as bands, ropes or strings, with which the sacks are closed once they have been filled with the required products, after a relative movement between the closing means and the mouth of the sacks, which is contracted to form folds or creases, whereupon clamps, seals or other conventional means are used to consolidate the closure of the previously filled sacks, which are then ready to be marketed and have an appropriate handle.
These sacks can have many different sizes, taking sacks to include bags, subject to their characteristics being as above, and the sacks can in any event carry suitable reinforcements at certain of their portions to resist the mechanical strain stemming from the weight to be borne and the actual handling and use thereof.
There were heretofore three systems for manipulating the sacks to be filled with the required products and their mouths later closed:
1) An operator places the open sack under a hopper by hand, the hopper unloads the product for such time and in such amount as may be required for the sack to be filled, unloading being carried out at will through a control activated by the operator.
2) An operator places the open sack under a semi-automatic machine clip, which machine has sack receiving means and holds its mouth by action of the operator, and a horizontal rotatory support and many stations at which the sacks are received as described, then fill and weigh, then at another station another operator pulls the band and hangs each sack from a hook, and at a final station another operator finally closes the sack availing of conventional means, such as clamps and the like.
3) And a variant of system 2) in which a semi-automatic machine which resembles the above machine is used, albeit with the machine finally closing the sack with a clamp.
The three prior art systems use a lot of labor, with the cost and time this entails and with a relatively low industrial yield, to the extent that the hourly production is dependent upon the skill of the operators involved in each of the systems.